C++ Interface Example for mocking Hardware

main.cpp

#include <iostream>

using namespace std;

/**
 * @brief Base Class
 *
 */
class Interface
{
public:
   /**
    * @brief pure virtual function providing the interface.
    *
    * @return string
    */
   virtual string run() = 0;
};

/**
 * @brief Hardware fulfilling the interface
 *
 */
class Hardware : public Interface
{
public:
   string run()
   {
      return "Hardware";
   }
};

/**
 * @brief Test fulfilling the interface,
 * but e.g. do nothing with actual hardware
 */

class Test : public Interface
{
public:
   string run()
   {
      return "Test";
   }
};

/**
 * @brief Example class using the interface
 */
class Caller
{
public:
   /**
    * @brief Reference to the interface
    */
   Interface &m_interface;

   /**
    * @brief Construct a new Caller object
    *
    * @param intf interface reference for the Caller
    */
   Caller(Interface &intf) : m_interface(intf){};

   /**
    * @brief Call the interface
    */
   void run()
   {
      cout << "Calling " << m_interface.run() << endl;
   }
};

int main(void)
{
   // Contructing the actual hardware object, give it to the caller and call it
   Hardware hw;
   Caller c_hw(hw);
   c_hw.run();

   // Contructing the test object, give it to the caller and call it
   Test t;
   Caller c_t(t);
   c_t.run();

   return 0;
}